Dear Forum members,

I am modeling hanger uisng "Hanger between two pipes" option, as per Caesar-II application guide, i followed the procedure as specified "Note: The directive Connect Geometry through CNodes must be disabled in Configuration Setup to avoid plot and geometry errors."

Actually, my model contain two arragements, which must be connected using hanger support, so when i disable the above said in configuration setup, the part of piping arrangement connected after the hanger support is moved to the origin (i.e.) to the first node of caesar file. Is this is how will happen or am i modelled wrongly.

Please clarify....

CNODES are used to connect or associate Degrees-of-Freedom, for the stiffness matrix. CNODES are also used to connect items graphically. There are two opposing situations in the "graphic space":

1) You connect a pipe nozzle to a vessel, using computed stiffnesses. In this case, you also want the CNODE to also connect the graphics (geometry) so the model looks right. Here you want CONNECT_GEOMETRY_THRU_CNODES turned on.

2) You associate two DOFs that are not at the same location (like you did with your hanger). In this case you want CONNECT_GEOMETRY_THRU_CNODES turned off, otherwise you foul up the geometry of the model.

You cannot satisfy both #1 and #2 in the same model. You have to turn off CONNECT_GEOMETRY_THRU_CNODES othewise the geometry is wrong. This may result in (graphically) disconnected pipe segements. You can usually address this with dummy rigid elements.

For example, in your case with the hanger, from the top pipe drop down with a dummy rigid element of the proper length, to reach the hanger location on the bottom pipe. Then when you specify the hanger on the bottom pipe, the CNODE will be the lower node of the dummy, not the node on the upper pipe. If you model this way, you can then keep CONNECT_GEOMETRY_THRU_CNODES turned on.

Mr. Richard,

Thanks for your reply. I tried as per your method, the geometry of the model is fine, but there is some marginal variation in the spring hanger report from the earlier method (i.e, making CONNECT_GEOMETRY_THRU_CNODES turned off) such as the horizontal movement varies from 4 mm to 7mm, hot load varies with a deviation of 10%.

Any how, the method suggested by you seems to be acceptable and i follow the same, hope the same shall be updated in the Caesar help guide.

Thankyou.